1. Field of the Invention
This invention relates to an indirect extrusion press and more particularly to an intermediate frame type indirect extrusion press.
2. Description of the Prior Art
A die stem in an indirect extrusion press usually has a cylindrical shape. In an indirect extrusion press of such a type wherein this stem is not capable of being disposed in and out of the direction of the press axis via a press platen, when a storing total press capacity is applied as a load in the axial direction of the die stem, a large bending moment occurs by even a slight eccentric quantity even if the die stem is suitably secured to the rear end portion of the press platen. It is necessary, but is difficult, to sufficiently cope with this bending moment. Hence, the accuracy of the die stem can not be maintained and in addition, the die stem is sometimes damaged. A large bending moment also acts on the die stem due to a shear force when a product is cut off from a discard after completion of the extrusion. As a result, core deviation of the die stem and breakage at the time of fitting occur, thus failing to extrude a product having an intended dimension.
To meet with the problem, research and development of various aparatuses has been made including a die stem back-up device such as disclosed by the inventor of this invention in Japanese Utility Model Laid-Open No. 110,382/1974, for example. However, none of them has yet been entirely satisfactory.
As a conclusion based on vast knowledges and versatile experiences in using press apparatuses and also as a result of subsequent research and development, the inventor of the present invention has now succeeded in developing a press apparatus having various additional features without sacrificing those of the prior press apparatus.